added install and uninstall hooks

tests/git_test.py

@@ -0,0 +1,42 @@
+
+import os
+import pytest
+
+from plumbum import local
+from pre_commit import git
+
+@pytest.fixture
+def empty_git_dir(tmpdir):
+    local.cwd.chdir(tmpdir.strpath)
+    local['git']['init']()
+    return tmpdir.strpath
+
+
+def test_get_root(empty_git_dir):
+    assert git.get_root() == empty_git_dir
+
+    foo = local.path('foo')
+    foo.mkdir()
+    local.cwd.chdir(foo)
+
+    assert git.get_root() == empty_git_dir
+
+
+def test_get_pre_commit_path(empty_git_dir):
+    assert git.get_pre_commit_path() == '{0}/.git/hooks/pre-commit'.format(empty_git_dir)
+
+
+def test_create_pre_commit(empty_git_dir):
+    git.create_pre_commit()
+    assert len(open(git.get_pre_commit_path(), 'r').read()) > 0
+
+
+def test_remove_pre_commit(empty_git_dir):
+    git.remove_pre_commit()
+
+    assert not os.path.exists(git.get_pre_commit_path())
+
+    git.create_pre_commit()
+    git.remove_pre_commit()
+
+    assert not os.path.exists(git.get_pre_commit_path())